The inventive concept relates to an image sensor and an image processing device including the same, and more particularly, to an image sensor which utilizes a calibration circuit to overcome a non-linearity condition, and to an image processing device including the same.
An image sensor senses light and converts the intensity of the light into digital image data. With the development of complementary metal oxide semiconductor (CMOS) technology, a CMOS image sensor (CIS) using CMOS technology is widely being used.
The CIS uses a dynamic range function and a wide dynamic range (WDR) function to provide a sharp image in an environment exhibiting a high luminance differential. The WDR function is realized using a well capacity adjusting method or a multiple sampling method in which a plurality of images of a scene taken at greatly different exposure times are combined to create a single image of the scene. The multiple sampling method has a favorable combination quality, but it requires a frame memory or a plurality of line memories since a plurality of images need to be combined with one another with time differences. The well capacity adjusting method also suffers drawbacks related to mixing images due to a large distribution of pixels and exhibits a non-linearity problem.
A dynamic range is defined as the range of response to the relative quantity of light that can be represented by a system. The lower limit of the dynamic range is restricted by the minimum quantity of light that can be represented or sensed by the system, and the upper limit thereof is a maximum quantity of light that can be sensed by the system. At the quality of light over the upper limit, a signal is saturated.